Systems and methods for optimizing engine operations in gensets

ABSTRACT

A system comprises a generator and an engine coupled thereto. The engine is configured to provide mechanical power to the generator. A controller is coupled to the engine and the generator and is configured to compare an engine operating parameter value to a load demand value indicative of a load exerted by the generator on the engine. The controller determines that the engine operating parameter value fails to match the load demand value. The controller determines an engine operating parameter threshold value at which the engine operating parameter value failed to match the load demand value, and sets the engine operating parameter threshold value as a maximum allowable engine operating parameter value for the engine.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to and benefit of U.S.Provisional Application No. 62/642,995, filed Mar. 14, 2018, andentitled “Systems and Methods for Optimizing Engine Operations inGensets,” which is incorporated herein by reference herein in itsentirety and for all purposes.

TECHNICAL FIELD

The present disclosure relates generally to control systems forpreventing stalling in engines included in or with generator sets(“gensets”).

BACKGROUND

Gensets such as those used in electrified vehicles include an enginecoupled to a generator. The generator produces electricity when drivenby the engine. Such gensets may be used, for example in hybrid vehiclesin which the genset provides intermittent power to drive the vehiclealong with a power source (e.g., batteries), or may be used in electricvehicles in range extender electric vehicles (REEV) as an on boardsource of electrical generation configured to provide electrical powerto the vehicle once the primary power source starts to run low. Theengine is generally matched to the generator so that the engine canmatch the load demand exerted by the generator on the engine.

Generally, the engines included in gensets have more variation in powerproduction than the generator. For example, a genset may be matchedduring calibration using a particular engine and generator combination,but when the genset is installed in a system (e.g., a vehicle), adifferent engine (e.g., a different engine of the same model) is usedwhich may be mismatched with the generator. Furthermore, the engine mayhave been calibrated to match the generator up to a certain load demand,but due to wear-and-tear during operation, or because of environmentalconditions, the engine may become mismatched from the generator. In suchinstances, the engine may be unable to match the load demand exerted onit by the generator. If the load demand exerted by the generator on theengine exceeds the power which the engine can produce, the engine maystall or lug and eventually shut down. Therefore, gensets are oftencontrolled so as to provide a large buffer between the actual ratedpower of the engine (e.g., 150 kW) and the load demand that thegenerator may exert on the engine (e.g., 130 kW) so as to accommodateany mismatch and prevent lugging and stalling. However, this oftenresults in the engine being used below the actual power that the enginemay be capable of providing to the generator, thereby reducing theperformance of the genset, and the system (e.g., a vehicle) includingthe genset.

SUMMARY

Embodiments described herein relate generally to systems and methods forpreventing stalling and/or lugging in an engine coupled to a generator.Particularly, systems and methods described herein are configured todynamically determine an engine operating parameter threshold valuecorresponding to a load demand value exerted by the generator on theengine at which the engine starts to stall, and set the value as amaximum allowable engine operating parameter value.

In some embodiments, a system comprises a generator, and an enginecoupled to the generator. The engine is configured to provide mechanicalpower to the generator. A controller is coupled to the engine and thegenerator. The controller is configured to compare an engine operatingparameter value to a load demand value indicative of a load exerted bythe generator on the engine. The controller is configured to determinethat the engine operating parameter value fails to match the load demandvalue. The controller is configured to determine an engine operatingparameter threshold value at which the engine operating parameter valuefailed to match the load demand value. The controller is furtherconfigured to set the engine operating parameter threshold value as amaximum allowable engine operating parameter value for the engine.

In some embodiments, a control system for a genset including an engineand a generator, comprises: a controller configured to be coupled toeach of the engine and the generator, the controller configured to:compare an engine operating parameter value to a load demand valueindicative of a load exerted by the generator on the engine; determinethat the engine operating parameter value fails to match the load demandvalue; determine an engine operating parameter threshold value at whichthe engine operating parameter value failed to match the load demandvalue; and set the engine operating parameter threshold value as amaximum allowable engine operating parameter value for the engine.

In some embodiments, a method for controlling a genset comprising anengine and a generator, comprises: comparing an engine operatingparameter value to a load demand value indicative of a load exerted bythe generator on the engine; determining that the engine operatingparameter value fails to match the load demand value; determining engineoperating parameter threshold value at which the engine operatingparameter value failed to match the load demand value; and setting theengine operating parameter threshold value as a maximum allowable engineoperating parameter value for the engine.

It should be appreciated that all combinations of the foregoing conceptsand additional concepts discussed in greater detail below (provided suchconcepts are not mutually inconsistent) are contemplated as being partof the subject matter disclosed herein. In particular, all combinationsof claimed subject matter appearing at the end of this disclosure arecontemplated as being part of the subject matter disclosed herein.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing and other features of the present disclosure will becomemore fully apparent from the following description and appended claimstaken in conjunction with the accompanying drawings. Understanding thatthese drawings depict only several implementations in accordance withthe disclosure and are therefore not to be considered limiting of itsscope, the disclosure will be described with additional specificity anddetail through use of the accompanying drawings.

FIG. 1 is a schematic illustration of a system comprising a gensetincluding an engine, a generator and a controller, according to anembodiment.

FIG. 2 is a schematic block diagram of the controller of FIG. 1,according to an embodiment.

FIG. 3 is a torque-speed curve of an engine included in a genset inresponse to an increasing load demand exerted by the generator of thegenset on the engine, and a speed threshold value of the engine.

FIG. 4A is a schematic flow diagram of a method for determining anengine operating parameter threshold value for an engine included in agenset, and setting the value as a maximum allowable engine operatingparameter value for the engine, according to an embodiment.

FIG. 4B is a schematic flow diagram of a method for determining a loaddemand threshold value for an engine included in a genset, and settingthe value as a maximum allowable load demand value for the engine,according to an embodiment.

Reference is made to the accompanying drawings throughout the followingdetailed description. In the drawings, similar symbols typicallyidentify similar components unless context dictates otherwise. Theillustrative implementations described in the detailed description,drawings, and claims are not meant to be limiting. Other implementationsmay be utilized, and other changes may be made, without departing fromthe spirit or scope of the subject matter presented here. It will bereadily understood that the aspects of the present disclosure, asgenerally described herein and illustrated in the figures, can bearranged, substituted, combined, and designed in a wide variety ofdifferent configurations, all of which are explicitly contemplated andmade part of this disclosure.

DETAILED DESCRIPTION

Embodiments described herein relate generally to systems and methods forpreventing stalling and/or lugging in an engine coupled to a generator.Particularly, systems and methods described herein are configured todynamically determine an engine operating parameter threshold valuecorresponding to a load demand value exerted by the generator on theengine at which the engine starts to stall, and set the value as amaximum allowable engine operating parameter value.

Various embodiments of the systems and methods described herein mayprovide benefits including, for example: (1) providing real timedetermination of a maximum allowable engine operating parameter (e.g.,speed, torque, power, etc.) that may be drawn from an engine by agenerator coupled thereto; (2) preventing stalling of the engine bypreventing the engine from going above the maximum allowable engineoperating parameter; (3) eliminating the use of a large buffer betweenengine power and load used in conventional engines, by allowing theengine to be operated up to the maximum allowable engine operatingparameter value; and (4) maximizing power output from the engine,thereby improving performance of the genset and a system (e.g., avehicle) including the genset.

FIG. 1 is a schematic illustration of a system 100 including a genset101, a power source 130 and a load 140. The system 100 may be anelectrified vehicle (e.g., a hybrid vehicle, a plug-in-hybrid vehicle, aREEV, etc.). In other embodiments, the system 100 may be an electricalpower production system, for example, a backup grid power generationsystem or a portable power generation system (e.g., a residential backuppower generation system). The genset 101 includes an engine 110, agenerator 120, and a controller 170 operably coupled to each of theengine 110 and the generator 120. The genset 101 may be configured togenerate back-up power so as to provide power to the power source 130and/or the load 140 in the event that a capacity of the power source 130decreases below a low capacity threshold. In some embodiments, thesystem 100 includes a REEV which is designed to primarily operate onelectric power. For example, the system 100 may be an on-road or anoff-road vehicle including, but not limited to, line-haul trucks,mid-range trucks (e.g., pick-up truck), cars (e.g., sedans, hatchbacks,coupes, etc.), buses, vans, refuse vehicles, delivery trucks,motorbikes, three wheelers, and any other type of vehicle structured touse electric power as the main electromotive force to drive its wheels.Thus, the present disclosure is applicable with a wide variety ofimplementations.

The power source 130 may be configured to store and provide electricpower to the load 140 which may include, for example one or more DCmotors included in the system 100. For example, the system 100 mayinclude an REEV, and the load 140 may include one or more DC motorscoupled to wheels included in the REEV. The power source 130 may includea battery such, as for example a lithium-ion battery, a lithium-airbattery, a lithium-sulfur battery, a sodium-ion battery or any otherelectric power source.

The engine 110 is coupled to the generator 120, and configured toprovide mechanical power to the generator 120, for example, in responseto a load demand by the generator 120 from the engine 110. The engine110 may include an internal combustion (“IC”) engine which converts fuel(e.g., diesel, gasoline, natural gas, biodiesel, ethanol, liquidpetroleum gas or any combination thereof.) into mechanical energy. Theengine 110 may include a plurality of piston and cylinders pairs (notshown) for combusting the fuel to produce mechanical energy.Furthermore, the engine 110 may be coupled to the generator 120 via ashaft so as to provide mechanical power thereto in response to the loaddemand exerted on the engine 110 by the generator 120.

The generator 120 may include an alternator, for example a wound rotoror permanent magnet alternator configured to convert a rotationalmechanical power produced by the engine 110 into electrical energy. Thegenerator 120 is configured to produce an electrical output. Theelectrical output can include a voltage and/or a current, and isproportion to the speed or torque provided by the engine 110 to thegenerator 120. The generator 120 is configured to exert a load demand onthe engine 110, for example based on a load demand (e.g., power, speedor torque) demanded by the load 140 and/or power source 130 from thegenerator 120.

Expanding further, in some instances a capacity of the power source 130(e.g., an amount of electrical charge stored in the power source 130)may drop below a low capacity threshold. The load 140 and/or the powersource 130 may request the generator 120 (e.g., via the controller 170described below in further detail herein) to generate electrical powerbased on a load requirement from the power source 130 and/or the load140. The generator 120 exerts a load demand on the engine 110 causingthe engine 110 to activate (e.g., turn ON or start). For example, theengine 110 may initially be in a deactivated state (e.g., turned OFF).The controller 170 may communicate an activation signal to the engine110 based on the load needed from the generator 120 causing the engine110 to activate (e.g., turn ON or start) which in turn drives thegenerator 120 so as to produce electrical power corresponding to theload demand.

The engine 110 adjusts an engine operating parameter thereof (e.g., viathe controller 170) so as to match the load demand exerted by thegenerator 120 thereon. The load demand may include, for example, amechanical power requested by the generator 120 from the engine 110, andthe engine operating parameter may include, for example an engine speed,an engine torque or otherwise, engine power produced by the engine 110corresponding to the load demand. For example, a user driving a vehicleincluding system 100 when the power source 130 is discharged, mayaccelerate the vehicle and increase a load demand on the generator 120,thereby causing the generator 120 to exert an increasing load demand onthe engine 110.

As used herein, the term “match,” or “matching” implies that a power, aspeed, a torque and/or an efficiency of the engine 120 is within apredefined range (e.g., as defined by the controller 170) of a power, aspeed, a torque, an efficiency, a voltage and/or current that thegenerator 120 may have to produce at so as to meet the load demand(e.g., the electrical power corresponding to the load demand thatgenerator 120 may have to produce). For example, the generator 120 mayhave to produce a power of 100 W based on a load demand, and the engine110 would be matched with the generator 120 if a power produced by theengine 110 is within +5% of the corresponding power that the generator120 should produce (i.e., in a range of 95 kW to 105 kW). Similarly, thegenerator 120 may have to be driven at 100 rpm to produce an electricalpower corresponding to a load demand, and the engine 110 would bematched with the generator 120 if a speed of the engine 110 is within+5% of the speed that the generator 120 should be driven at (i.e., in arange of 95 rpm to 105 rpm).

Alternatively, the genset 101 may be rated at a particular power factor.Power factor is defined as the ratio of real power (kW) (i.e., a powerproduced by the engine 110) to apparent power (kVA) (i.e., a powerproduced by the generator 120), and is a number between 0 and 1. Thus, a0.8 power factor implies that the genset 120 producing 100 kVA ofelectrical power corresponds to the engine 110 producing 80 KW of realpower. The engine 110 and generator 120 may be “matched” if the actualpower factor of the genset 101 is within +5% (e.g., in a range of 0.75to 0.85) of the rated power factor of the genset 101 (e.g., 0.8).

In some instances, the engine 110 may be mismatched from the generator120 such that the engine 110 has at least one of a peak torque, peakpower or peak speed which is less than (e.g., less than 95%) at leastone of a peak torque, peak power or peak speed, respectively of thegenerator 120. For example, the engine 110 may be rated at a lower powerthan the generator 120, may be different than an engine that thegenerator 120 was originally matched with, or may have become mismatchedfrom the generator 120 due to wear-and-tear. As used herein, the term“mismatch” implies that at least under some conditions, the engine 110is not able to match, cope or otherwise provide mechanical energy orpower to match a load demand value (e.g., an amount of power) requiredby the generator 120 from the engine 110, thereby possibly leading tostalling or lugging of the engine 110, unwanted wear and tear andgenerally inefficient operation of the engine. The engine 110 may be“mismatched” with the generator 120 when one or more of the matchcriteria are not met. For example, at certain load demands, the genset101 may have an actual power factor which is beyond an acceptable rangeof the rated power factor of the genset 101 (e.g., lower than 0.75 orhigher than 0.85 for a rated power factor of 0.8). A leading powerfactor below 0.75 may result in the engine 110 having surplus real powerto power the generator 120 in excess of its 100% kVA rating. Similarly,a lagging power factor above 0.8 results in the engine 110 not havingsufficient real power to power the generator 120 to 100% of its kVArating, which may lead to stalling, lugging, or premature stopping ofthe engine 110.

As shown in FIG. 1, the controller 170 is coupled to the engine 110 andthe generator 120. In some embodiments, the controller 170 may also becoupled to the power source 130 and/or the load 140. For example, thecontroller 170 may be configured to determine the capacity of the powersource 130, and activate (e.g., turn ON) the engine 110 when thecapacity of the power source 130 decreases below the low capacitythreshold. Furthermore, the controller 170 may also be configured todeactivate (e.g., turn OFF) the engine 110 when the capacity of thepower source 130 reaches a high capacity threshold (e.g., the powersource 130 is fully charged). The controller 170 may be configured todetermine a load demand exerted by the load 140 on the generator 120. Inparticular embodiments, the controller 170 may be coupled to a centralcontroller (not shown) configured to control the overall operation ofthe system 100. In such embodiments, the controller 170 may activate ordeactivate the engine 110 based on an input from the central controller.

The controller 170 may be operably coupled to the engine 110, thegenerator 120, the power source 130, the load 140 and/or any othercomponents of the system 100 using any type and any number of wired orwireless connections. For example, a wired connection may include aserial cable, a fiber optic cable, a CATS cable, or any other form ofwired connection. Wireless connections may include the Internet, Wi-Fi,cellular, radio, Bluetooth, ZigBee, etc. In one embodiment, a controllerarea network (CAN) bus provides the exchange of signals, information,and/or data. The CAN bus includes any number of wired and wirelessconnections. Because the controller 170 is communicably coupled to thesystems and components of the system 100 as shown in FIG. 1, thecontroller 170 is structured to receive data regarding one or more ofthe components shown in FIG. 1. For example, the data may include anengine operating parameter value from the engine 110 (e.g., an amount ofspeed, power, torque or any other suitable engine operating parameter),a load demand value exerted by the generator 120 on the engine 110(e.g., an amount of power demanded by the generator 120 from engine110), a capacity of the power source 130 and/or the load demand exertedby the load 140 on the generator 120. The controller 170 may determinehow to control the engine 110 and/or the generator 120 based on theoperation data, as described herein.

The controller 170 is configured to dynamically (e.g., while thegenerator 120 and the engine 110 are operating in real time orsubstantially real time) determine an engine operating parameterthreshold value corresponding to a load demand value exerted by thegenerator 120 on the engine 110, at which the engine 110 starts tostall, lug or otherwise an operation thereof is adversely affected, andset the value as a maximum allowable engine operating parameter value.Expanding further, the controller 170 is configured to compare an engineoperating parameter value to a load demand value corresponding to theload demand. The engine operating parameter value is configured toadjust so as to match the load demand value as the load demand valuechanges over time.

For example, the engine operating parameter value may include a value ofthe speed, torque or power of the engine 110 and the load demand valuemay include a value of a power demand exerted by the generator 120 onthe engine 110 (e.g., based on the power required by the load 140). Thecontroller 170 may include algorithms or lookup tables configured tocompare the engine operating parameter value (e.g., engine speed) to theload demand value (e.g., power demand) and adjust the engine operatingparameter value to match the load demand value as the load demand valuechanges over time (e.g., increases or decreases).

The controller 170 is configured to determine that the engine operatingparameter value fails to match the load demand value. For example, theload demand exerted by the generator 120 on the engine 110 may continueto increase and the controller 170 may be configured to adjust (e.g.,increase) the engine operating parameter value so as to match the loaddemand value (e.g., increase the speed of the engine 110 to increase apower output of the engine 110 so as to match the power required by thegenerator 120 therefrom) until the engine 110 reaches a limit. Anyfurther increase in the load demand value may not result in acorresponding increase in the engine operating parameter value, and mayactually cause the engine operating parameter value to decrease (e.g.,the engine speed may start to decrease) indicative of the engine 110stalling or lugging (e.g., an unusually sudden drop in engine 110 speedand/or torque).

The controller 170 is configured to determine an engine operatingparameter threshold value corresponding to the load demand value atwhich the engine parameter value failed to match the load demand value.For example, the controller 170 may store (e.g., in the memory 173 asdescribed with respect to FIG. 2) the maximum value of the engineoperating parameter (e.g., maximum speed) that the engine 110 was ableto achieve to match the load demand value, and any further increase inthe load demand value caused the engine operating value to remain thesame or decrease thereafter. As previously described herein, the loaddemand value being greater than the engine operating parameter thresholdvalue corresponds to the engine 110 stalling, and the controller 170 maybe configured to turn OFF or shut OFF the engine 110 in response to theload demand value being greater than the engine operating parameterthreshold value to prevent the engine 110 from stalling.

Furthermore, the controller 170 may be configured to set the engineoperating parameter threshold value as a maximum allowable engineoperating parameter value for the engine 110. In other words, thecontroller 170 sets an upper limit for the engine operating parametervalue corresponding to an actual power output that the engine 110 iscapable of producing. This allows more power to be drawn from the engine110 in contrast to conventional gensets that employ a pre-defined upperlimit by providing a large buffer between the load demand value and theengine operating parameter value, which prevents the engine 110 frombeing pushed to its maximum capability. In particular embodiments, thecontroller 170 may also be configured to maintain the engine operatingparameter value below the engine operating parameter threshold value soas to prevent lugging or stalling of the engine 110.

In particular embodiments, the controller 170 may be further configuredto determine a load demand threshold value corresponding to the engineoperating parameter value at which the engine operating parameter valuefailed to match the load demand value. For example, the controller 170may determine a specific load demand value at which the engine operatingparameter value started mismatching (e.g., immediately or within a shorttime period such as less than 5 seconds) from the load demand value(e.g., subsequent increase in load demand value did not cause acorresponding increase, or resulted in decrease of the engine operatingparameter value), and store the value as the load demand threshold valuein the memory thereof (e.g., the memory 173). The controller 170 may setthe load demand threshold value as a maximum allowable load demand valuefor the generator 120, for example, the maximum power draw the generator120 may exert on the engine 110. In some embodiments, the controller 170is also configured to maintain the load demand value below the loaddemand threshold value. In other words, the controller 170 may preventthe generator 120 from exerting a load demand value on the engine 110,which is greater than the engine operating parameter threshold, so as toprevent lugging or stalling of the engine 110.

In some embodiments, the controller 170 may be configured to determineand set the engine operating parameter threshold value and/or the loaddemand threshold value during an initial run (e.g., a calibration run, atest run, or a first operational run) of the genset 101 in the system100. In other embodiments, the controller 170 may be configured toperiodically determine and update the engine operating parameterthreshold value and/or the load demand threshold value over the life ofthe system 100. For example, the controller 170 may determine and updatethe engine operating parameter threshold value and/or the load demandthreshold value at each maintenance interval or any other predeterminedinterval, so as to accommodate for degradation (e.g., due towear-and-tear) or enhancement (e.g., due to modifications such asinstallation of a turbocharger or supercharger) in the performance ofthe engine 110. In this manner, the controller 170 may enable maximumpower to be drawn from the engine 110 by the generator 120 based on anactual performance capability of the engine 110, rather than apre-defined limit.

In various embodiments, the controller 170 may comprise an electroniccontrol unit configured to receive various signals from the engine 110,the generator 120 and optionally, the power source 130 and the load 140.As shown in FIG. 2, the controller 170 may include a processing circuit171 having a processor 172 and a memory 173, an engine parametermonitoring circuit 174, a generator load monitoring circuit 176, acomparison circuit 178 and a communications interface 190. Thecontroller 170 may also include a response management circuitry 180having an engine parameter control circuit 182 and a generator loadcontrol circuit 184.

The processor 172 may comprise a microprocessor, programmable logiccontroller (PLC) chip, an ASIC chip, or any other suitable processor.The processor 172 is in communication with the memory 173 and configuredto execute instructions, algorithms, commands, or otherwise programsstored in the memory 173. The memory 173 may comprise any of the memoryand/or storage components discussed herein. For example, memory 173 maycomprise a RAM and/or cache of processor 172. The memory 173 may alsocomprise one or more storage devices (e.g., hard drives, flash drives,computer readable media, etc.) either local or remote to the controller170. The memory 173 is configured to store look up tables, algorithms,or instructions.

In one configuration, the engine parameter monitoring circuit 174, thegenerator load monitoring circuit 176, the comparison circuit 178, andthe response management circuitry 180 are embodied as machine orcomputer-readable media (e.g., stored in the memory 173) that isexecutable by a processor, such as the processor 172. As describedherein and amongst other uses, the machine-readable media (e.g., thememory 173) facilitates performance of certain operations to enablereception and transmission of data. For example, the machine-readablemedia may provide an instruction (e.g., command, etc.) to, e.g., acquiredata. In this regard, the machine-readable media may includeprogrammable logic that defines the frequency of acquisition of the data(or, transmission of the data). Thus, the computer readable media mayinclude code, which may be written in any programming languageincluding, but not limited to, Java or the like and any conventionalprocedural programming languages, such as the “C” programming languageor similar programming languages. The computer readable program code maybe executed on one processor or multiple remote processors. In thelatter scenario, the remote processors may be connected to each otherthrough any type of network (e.g., CAN bus, etc.).

In another configuration, the engine parameter monitoring circuit 174,the generator load monitoring circuit 176, the comparison circuit 178and the response management circuitry 180 are embodied as hardwareunits, such as electronic control units. As such, the engine parametermonitoring circuit 174, the generator load monitoring circuit 176, thecomparison circuit 178 and the response management circuitry 180 may beembodied as one or more circuitry components including, but not limitedto, processing circuitry, network interfaces, peripheral devices, inputdevices, output devices, sensors, etc. In some embodiments, the engineparameter monitoring circuit 174, the generator load monitoring circuit176, the comparison circuit 178 and the response management circuitry180 may take the form of one or more analog circuits, electroniccircuits (e.g., integrated circuits (IC), discrete circuits, system on achip (SOCs) circuits, microcontrollers, etc.), telecommunicationcircuits, hybrid circuits, and any other type of “circuit.” In thisregard, the engine parameter monitoring circuit 174, the generator loadmonitoring circuit 176, the comparison circuit 178 and the responsemanagement circuitry 180 may include any type of component foraccomplishing or facilitating achievement of the operations describedherein. For example, a circuit as described herein may include one ormore transistors, logic gates (e.g., NAND, AND, NOR, OR, XOR, NOT, XNOR,etc.), resistors, multiplexers, registers, capacitors, inductors,diodes, wiring, and so on.

Thus, the engine parameter monitoring circuit 174, the generator loadmonitoring circuit 176, the comparison circuit 178, and/or the responsemanagement circuitry 180 may also include programmable hardware devicessuch as field programmable gate arrays, programmable array logic,programmable logic devices or the like. In this regard, the engineparameter monitoring circuit 174, the generator load monitoring circuit176, the comparison circuit 178 and the response management circuitry180 may include one or more memory devices for storing instructions thatare executable by the processor(s) of the engine parameter monitoringcircuit 174, the generator load monitoring circuit 176, the comparisoncircuit 178, and the response management circuitry 180. The one or morememory devices and processor(s) may have the same definition as providedbelow with respect to the memory 173 and the processor 172.

In the example shown, the controller 170 includes the processing circuit171 having the processor 172 and the memory 173. The processing circuit171 may be structured or configured to execute or implement theinstructions, commands, and/or control processes described herein withrespect the engine parameter monitoring circuit 174, the generator loadmonitoring circuit 176, the comparison circuit 178, and the responsemanagement circuitry 180. Thus, the depicted configuration representsthe aforementioned arrangement where the engine parameter monitoringcircuit 174, the generator load monitoring circuit 176, the comparisoncircuit 178, and the response management circuitry 180 are embodied asmachine or computer-readable media. However, as mentioned above, thisillustration is not meant to be limiting as the present disclosurecontemplates other embodiments such as the aforementioned embodiment theengine parameter monitoring circuit 174, the generator load monitoringcircuit 176, the comparison circuit 178, and the response managementcircuitry 180 are configured as a hardware unit. All such combinationsand variations are intended to fall within the scope of the presentdisclosure.

The processor 172 may be implemented as one or more general-purposeprocessors, an application specific integrated circuit (ASIC), one ormore field programmable gate arrays (FPGAs), a digital signal processor(DSP), a group of processing components, or other suitable electronicprocessing components. In some embodiments, the one or more processorsmay be shared by multiple circuits (e.g., the engine parametermonitoring circuit 174, the generator load monitoring circuit 176, thecomparison circuit 178, and the response management circuitry 180 maycomprise or otherwise share the same processor which, in some exampleembodiments, may execute instructions stored, or otherwise accessed, viadifferent areas of memory). Alternatively, or additionally, the one ormore processors may be structured to perform or otherwise executecertain operations independent of one or more co-processors. In otherexample embodiments, two or more processors may be coupled via a bus toenable independent, parallel, pipelined, or multi-threaded instructionexecution. All such variations are intended to fall within the scope ofthe present disclosure. The memory 173 (e.g., RAM, ROM, Flash Memory,hard disk storage, etc.) may store data and/or computer code forfacilitating the various processes described herein. The memory 173 maybe communicably connected to the processor 172 to provide computer codeor instructions to the processor 172 for executing at least some of theprocesses described herein. Moreover, the memory 173 may be or includetangible, non-transient volatile memory or non-volatile memory.Accordingly, the memory 173 may include database components, object codecomponents, script components, or any other type of informationstructure for supporting the various activities and informationstructures described herein.

The communications interface 190 may include wireless interfaces (e.g.,jacks, antennas, transmitters, receivers, transceivers, wire terminals,etc.) for conducting data communications with various systems, devices,or networks. For example, the communications interface 190 may includean Ethernet card and port for sending and receiving data via anEthernet-based communications network and/or a Wi-Fi transceiver forcommunicating with engine 110, the generator 120, and optionally, thepower source 130, and/or the load 140. The communications interface 190may be structured to communicate via local area networks or wide areanetworks (e.g., the Internet, etc.) and may use a variety ofcommunications protocols (e.g., IP, LON, Bluetooth, ZigBee, radio,cellular, near field communication, etc.).

The engine parameter monitoring circuit 174 is configured to receiveengine operating parameter signals (e.g., data, values, information,etc.) from the engine 110 indicative of the engine operating parameterand determine the engine operating parameter value therefrom. Forexample, the engine parameter monitoring circuit 174 may be coupled to aspeed sensor or a tachometer coupled to the engine 110 and configured toreceive and interpret the engine operating parameter signals therefrom,the engine operating parameter signals being indicative of the speed ofthe engine 110.

The generator load monitoring circuit 176 is configured to receive loadsignals (e.g., data, values, information, etc.) from the generator 120indicative of the load demand exerted by the generator 120 on the engine110, and determine the load demand value therefrom. For example, a loadsensor may be coupled to the generator 120 and configured to measure apower (i.e., the load demand) exerted by the generator 120 on the engine110 (e.g., by measuring a current amplitude and phase difference betweenvoltage and current at an output of the generator 120). The generatorload monitoring circuit 176 may be coupled to the load sensor andconfigured to receive and interpret the load signals so as to determinethe power demanded by the generator 120 from the engine 110.

The comparison circuit 178 is configured to compare the engine operatingparameter value (e.g., an engine speed, torque or power) to the loaddemand value corresponding to the load demand (e.g., a power).Furthermore, the comparison circuit 178 may determine that the engineoperating parameter value fails to match the load demand value, aspreviously described herein.

The response management circuitry 180 is structured to instruct theengine 110 to adjust the engine operating parameter value so as to matchor substantially match the load demand value as the load demand valuechanges over time. Furthermore, the response management circuitry 180may be configured to dynamically determine the engine operatingparameter threshold value corresponding to a load demand value exertedby the generator 120 on the engine 110 at which the engine 110 starts tostall, and set the value as a maximum allowable engine operatingparameter value.

Expanding further, in response to determining that the engine operatingparameter value fails to match the load demand value, the engineparameter control circuit 182 may determine an engine operatingparameter threshold value corresponding to the load demand value atwhich the engine parameter value failed to match the load demand value.Furthermore, the engine parameter control circuit 182 may set the engineoperating parameter threshold value as a maximum allowable engineoperating parameter value for the engine 110, as previously describedherein. The engine parameter control circuit 182 may also be configuredto maintain the engine operating parameter value below the engineoperating parameter value threshold, so as to prevent stalling orlugging of the engine 110.

In other embodiments, in response to the determining that the engineoperating parameter value failed to match the load demand value, thegenerator load control circuit 184 may determine a load demand thresholdvalue corresponding to the engine operating parameter value at which theengine parameter value failed to match the load demand value. Thegenerator load control circuit 184 may set the engine operatingparameter threshold value as a maximum allowable load demand value forthe generator 120, as previously described herein. Moreover, thegenerator load control circuit 184 may also be configured to maintainthe load demand value below the load demand threshold value, so as toprevent stalling or lugging of the engine 110.

FIG. 3 is an example speed-torque curve demonstrating the response of anengine coupled to a generator for use in a REEV. The speed of the engineis increased in response to an increasing load demand from the engine.The speed of the engine continues to increase until it reaches a speedthreshold value, at which the engine is no longer able to match the loaddemand requested from the generator. Any further increase in a loaddemand value causes a decrease in the engine speed corresponding to theengine stalling or lugging, and may lead to engine shut down. The speedthreshold value may be set (e.g., by a controller, such as thecontroller 170 coupled to the engine and the generator) as the maximumallowable speed value for the engine, and the engine speed may bemaintained below this value, for example by restricting the load demand,thereby preventing stalling or lugging of the engine while enablingmaximum possible power draw from the engine.

FIG. 4A is a schematic flow diagram of an example method 200 forpreventing stalling and lugging in an engine (e.g., the engine 110)coupled to a generator (e.g., the generator 120) included in a genset(e.g., the genset 101) and allowing maximum power to be drawn from theengine. The engine may be mismatched from the generator, at least atcertain operating conditions. While described with respect to the system100 and the genset 101, the operations of the method 200 are applicationto any number of gensets included in any system, for example a hybridvehicle, a plug-in-hybrid vehicle, a REEV or any other system whichincludes a genset. As such the operations of the method 200 may beimplemented with the engine 110, the generator 120 and the controller170, and are therefore described with respect to FIGS. 1-2.

In some embodiments, the engine parameter monitoring circuit 174monitors an engine operating parameter value of the engine 110, at 202.For example, the engine parameter monitoring circuit 174 may beconfigured to receive engine operating parameter signals from the engine110 (e.g., from a speed sensor, load sensor or tachometer coupledthereto) indicative of the engine operating parameter and determine theengine operating parameter value therefrom.

The comparison circuit 178 determines if the engine operating parametervalue matches the load demand value, at 204. For example, the comparisoncircuit 178 may be configured to compare the engine operating parametervalue (e.g., an engine speed, torque or power) to the load demand valuecorresponding to the load demand (e.g., a power) so as to determine ifthe engine operating parameter value matches the load demand value.

If the engine operating parameter value matches the load demand value,the comparison circuit 178 continues to compare the engine operatingparameter value to the load demand value (e.g., the method 200 returnsto operation 202). In response to determining that the engine operatingparameter value fails to match the load demand value, the engineparameter control circuit 182 determines an engine operating parameterthreshold value, at 206. For example, if the comparison circuit 178determines that the engine operating parameter value fails to match theload demand value, the engine parameter control circuit 182 maydetermine the engine operating parameter threshold value correspondingto the load demand value at which the engine parameter value failed tomatch the load demand value.

The engine parameter control circuit 182 may set the engine operatingparameter threshold value as a maximum allowable engine operatingparameter value for the engine 110, at 208. Furthermore, the engineparameter control circuit 182 maintains the engine operating parametervalue below the engine operating parameter value threshold, at 210, soas to prevent stalling or lugging of the engine 110.

FIG. 4B is a schematic flow diagram of another example method 300 forpreventing stalling and lugging in an engine (e.g., the engine 110)coupled to a generator (e.g., the generator 120) included in a genset(e.g., the genset 101) and allowing maximum power to be drawn from theengine. The engine may be mismatched from the generator, at least atcertain operating conditions. While described with respect to the system100 and the genset 101, the operations of the method 300 are applicationto any number of gensets included in any system, for example, a hybridvehicle, a plug-in-hybrid vehicle, a REEV or any other system whichincludes a genset. As such the operations of the method 300 may beimplemented with the engine 110, the generator 120 and the controller170, and are therefore described with respect to FIGS. 1-2.

The engine parameter monitoring circuit 174 monitors an engine operatingparameter value of the engine 110, at 302. For example, the engineparameter monitoring circuit 174 may be configured to receive engineoperating parameter signals from the engine 110 (e.g., from a speedsensor, load sensor or tachometer coupled thereto) indicative of theengine operating parameter and determine the engine operating parametervalue therefrom.

The generator load monitoring circuit 176 monitors a load demand valuedemanded by the generator 120 from the engine 110, at 304. For example,the generator load monitoring circuit 176 may be configured to receiveload signals from the generator 120 (e.g., from a load sensor coupledthereto) indicative of the load demand exerted by the generator 120 onthe engine 110, and determine the load demand value therefrom.

The comparison circuit 178 determines if the engine operating parametervalue matches the load demand value, at 306. In response to thedetermining that the engine operating parameter value failed to matchthe load demand value, the generator load control circuit 184 maydetermine a load demand threshold value, at 308. The load demand valuecorresponds to the engine operating parameter value at which the engineparameter value fails to match the load demand value. The generator loadcontrol circuit 184 sets the engine operating parameter threshold valueas a maximum allowable load demand value for the generator 120, at 310.Moreover, the generator load control circuit 184 also maintains the loaddemand value below the load demand threshold value, at 312 so as toprevent stalling or lugging of the engine 110. In various embodiments,the operations of methods 200 and 300 may be combined so that the engineoperating parameter maybe maintained below the engine operatingparameter threshold value, and the load demand maybe maintained belowthe load demand threshold value.

Although an example computing device has been described in FIG. 2,implementations described in this specification can be implemented inother types of digital electronic, or in computer software, firmware, orhardware, including the structures disclosed in this specification andtheir structural equivalents, or in combinations of one or more of them.

It should be noted that the term “example” as used herein to describevarious embodiments is intended to indicate that such embodiments arepossible examples, representations, and/or illustrations of possibleembodiments (and such term is not intended to connote that suchembodiments are necessarily extraordinary or superlative examples).

The term “coupled” and the like as used herein mean the joining of twomembers directly or indirectly to one another. Such joining may bestationary (e.g., permanent) or moveable (e.g., removable orreleasable). Such joining may be achieved with the two members or thetwo members and any additional intermediate members being integrallyformed as a single unitary body with one another or with the two membersor the two members and any additional intermediate members beingattached to one another.

It is important to note that the construction and arrangement of thevarious exemplary embodiments are illustrative only. Although only a fewembodiments have been described in detail in this disclosure, thoseskilled in the art who review this disclosure will readily appreciatethat many modifications are possible (e.g., variations in sizes,dimensions, structures, shapes and proportions of the various elements;values of parameters, mounting arrangements; use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter described herein.Additionally, it should be understood that features from one embodimentdisclosed herein may be combined with features of other embodimentsdisclosed herein as one of ordinary skill in the art would understand.Other substitutions, modifications, changes, and omissions may also bemade in the design, operating conditions, and arrangement of the variousexemplary embodiments without departing from the scope of the presentembodiments.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyembodiments or of what may be claimed, but rather as descriptions offeatures specific to particular implementations of particularembodiments. Certain features described in this specification in thecontext of separate implementations can also be implemented incombination in a single implementation. Conversely, various featuresdescribed in the context of a single implementation can also beimplemented in multiple implementations separately or in any suitablesubcombination. Moreover, although features may be described above asacting in certain combinations and even initially claimed as such, oneor more features from a claimed combination can in some cases be excisedfrom the combination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

What is claimed is:
 1. A system, comprising: a generator; an enginecoupled to the generator, the engine configured to provide mechanicalpower to the generator; and a controller coupled to the engine and thegenerator, the controller configured to: compare an engine operatingparameter value to a load demand value indicative of a load exerted bythe generator on the engine, determine that the engine operatingparameter value fails to match the load demand value, determine anengine operating parameter threshold value at which the engine operatingparameter value failed to match the load demand value, and set theengine operating parameter threshold value as a maximum allowable engineoperating parameter value for the engine.
 2. The system of claim 1,wherein the controller is further configured to adjust the engineoperating parameter value to match the load demand value as the loaddemand value changes over time.
 3. The system of claim 1, wherein thecontroller is further configured to: maintain the engine operatingparameter value below the engine operating parameter threshold value. 4.The system of claim 1, wherein the engine operating parameter valuecomprises at least one of an engine speed, an engine power or an enginetorque.
 5. The system of claim 1, wherein when the load demand value isgreater than the engine operating parameter threshold value, thecontroller is configured to turn off the engine to prevent the enginefrom stalling.
 6. The system of claim 1, wherein the controller isfurther configured to: determine a load demand threshold valuecorresponding to the engine operating parameter value at which theengine operating parameter value failed to match the load demand value,and set the load demand threshold value as a maximum allowable loaddemand value for the generator.
 7. The system of claim 6, wherein thecontroller is further configured to: maintain the load demand valuebelow the load demand threshold value.
 8. The system of claim 1, whereinthe engine is mismatched with the generator such that the engine has atleast one of a peak torque, peak power or peak speed which is less thanat least one of a peak torque, peak power or peak speed, respectively,of the generator.
 9. A control system for a genset that includes anengine and a generator, the control system comprising: a controllerconfigured to be coupled to each of the engine and the generator, thecontroller configured to: compare an engine operating parameter value toa load demand value indicative of a load exerted by the generator on theengine; determine that the engine operating parameter value fails tomatch the load demand value; determine an engine operating parameterthreshold value at which the engine operating parameter value failed tomatch the load demand value; and set the engine operating parameterthreshold value as a maximum allowable engine operating parameter valuefor the engine.
 10. The control system of claim 9, wherein thecontroller is configured to adjust the engine operating parameter valueso as to match the load demand value as the load demand value changesover time.
 11. The control system of claim 9, wherein the controller isfurther configured to: maintain the engine operating parameter valuebelow the engine operating parameter threshold value.
 12. The controlsystem of claim 9, wherein the engine operating parameter valuecomprises at least one of an engine speed, an engine power or an enginetorque.
 13. The control system of claim 9, wherein when the load demandvalue is greater than the engine operating parameter threshold value,the controller is configured to turn off the engine to prevent theengine from stalling.
 14. The control system of claim 9, wherein thecontroller is further configured to: determine a load demand thresholdvalue at which the engine operating parameter value failed to match theload demand value; and set the load demand threshold value as a maximumallowable load demand value for the generator.
 15. The control system ofclaim 14, wherein the controller is further configured to: maintain theload demand value below the load demand threshold value.
 16. A methodfor controlling a genset that includes an engine and a generator,comprising: comparing an engine operating parameter value to a loaddemand value indicative of a load exerted by the generator on theengine; determining that the engine operating parameter value fails tomatch the load demand value; determining an engine operating parameterthreshold value at which the engine operating parameter value failed tomatch the load demand value; and setting the engine operating parameterthreshold value as a maximum allowable engine operating parameter valuefor the engine.
 17. The method of claim 16, further comprising adjustingthe engine operating parameter value to match the load demand value asthe load demand value changes over time.
 18. The method of claim 16,further comprising: maintaining the engine operating parameter valuebelow the engine operating parameter threshold value.
 19. The method ofclaim 16, further comprising: determining a load demand threshold valuecorresponding to the engine operating parameter value at which theengine operating parameter value failed to match the load demand value;and setting the load demand threshold value as a maximum allowable loaddemand value for the generator.
 20. The method of claim 19, furthercomprising: maintaining the load demand value below the load demandthreshold value.